Abstract

We present a benchmark study of a combined multipole shielding polarizability/reaction field (MSP/RF) approach to the calculation of both specific and bulk solvation effects on nuclear magnetic shielding constants of solvated molecules. The MSP/RF scheme is defined by an expansion of the shielding constants of the solvated molecule in terms of electric field and field gradient property derivatives derived from single molecule ab initio calculations. The solventelectric field and electric field gradient are calculated based on data derived from molecular dynamics simulations, thereby accounting for solute–solvent dynamical effects. The MSP/RF method is benchmarked against polarizable quantum mechanics/molecular mechanics (QM/MM) calculations. The best agreement between the MSP/RF and QM/MM approaches is found by truncating the electric field expansion in the MSP/RF approach at the linear electric field level which is due to the cancelation of errors. In addition, we investigate the sensitivity of the results due to the choice of one-electron basis set in the ab initio calculations of the property derivatives and find that these derivatives are affected by the basis set in a way similar to the shielding constants themselves.

Received 15 November 2010Accepted 04 January 2011Published online 25 January 2011

Acknowledgments:

The authors thank the Danish Center for Scientific Computing (DCSC) for the computational resources and the Danish Natural Science Research Council/The Danish Councils for Independent Research for financial support. S.P.A.S. thanks the Carlsberg Foundation, and J.K. thanks the Lundbeck Foundation for financial support.